I've been using this app as a replacement for ntfy, and after a few days of use, I'm thrilled to report that Nextcloud App works flawlessly! In fact, I think it even outperforms ntfy in some aspects.
My main use case is pushing notifications from Matrix and Mastodon using uppush/NextPush. If you're looking for a getting started guide or want to learn more about the app, I highly recommend checking out the Codeberg Repository for NextPush. Overall, I'm really impressed with this app's performance and functionality - give it a try if you haven't already!